Unlockables

Ability to change weapons whenever you want

Just beat hard mode (with or without continues) to unlock the capacity to use select any weapon at anytime using L and R. Hard mode itself is unlocked by beating normal mode. Careful though : the weapons still have limited ammo and when out, you will have to cycle through the arsenal again to find the weapon you were using. To prevent that, tap L and then R (or vice versa) to reload the ammo.